What Are the Potential Physical Health Effects From the Gulf Oil Spill?

An Expert Interview With Vikas Kapil, DO, MPH, From the US Centers for Disease Control and Prevention

Janet Kim, MPH


July 23, 2010

Medscape: The breadth of this type of disaster is unheard of in this country, and its potential toll on human health has yet to be fully determined. Exposure to oil appears to affect multiple systems of the body; however, few human studies or experiences are available that provide actual guidance on what to expect. What might be extrapolated from existing data about the potential acute or short-term physical health effects?

Dr. Kapil: Any potential acute or short-term health effects are generally dependent on amount and duration of exposure. Prolonged skin contact with crude oil and petroleum products can cause skin erythema, edema, and burning. Swallowing crude oil, unless in large quantities -- for example, greater than 8 oz -- is unlikely to result in more than transient nausea, vomiting, gastrointestinal tract disturbances, and diarrhea. Ocular exposure can cause chemical conjunctivitis. Serious ocular injury is uncommon in the absence of other contaminants. Exposure to fresh crude oil may result in inhalation of associated vapors from volatile hydrocarbon components. Symptoms may include headache, dizziness, confusion, nausea, or vomiting.

Heat-related illness, such as heat stroke, heat exhaustion, heat cramps, or fainting, related to cleanup of the oil spill is an important health concern, particularly for responders. In addition, workers, volunteers, and residents of affected communities may experience stress and fatigue and may also be at risk for more serious mental health consequences. It's important that responders and residents of affected communities monitor their health and well-being closely and seek professional medical and/or mental health assistance when indicated.

Additional information on prevention and management of acute health effects, including heat illness and mental health aspects, is available on the CDC [CDC: Gulf Oil Spill 2010: Information for Health Professionals; CDC: NIOSH Workplace Safety & Health Topics: Deepwater Horizon Response: Gulf of Mexico Oil Cleanup] and Substance Abuse and Mental Health Services Administration (SAMSHA) Websites [SAMSHA: Find Substance Abuse and Mental Health Treatment; SAMSHA Disaster Response: Mental Health Awareness in Times of Emotional Distress]. Another useful resource is the National Suicide Prevention Lifeline at 1-800-273-TALK [1-800-273-8255].

Medscape: One of the main concerns is whether this exposure to the oil spill might promote the development of a malignancy in the future. What do you anticipate to be possible malignancies or other chronic health effects?

Dr. Kapil: Questions about long-term human health effects are important and complex. Little research has been conducted to examine the long-term health consequences of oil spills and related human exposures, including cancer outcomes. Much of what we know is from our experience with occupational exposure to crude and refined oil among oil workers, and a few limited studies of previous oil spills that primarily focused on short-term health outcomes. Findings from these previous studies are difficult to extrapolate for the current situation because many differences exist in the nature of the exposures and other related circumstances.

We can also look at the limited toxicity data related to individual components of the oil or dispersants. Evaluation of the impact of exposures is complicated due to a number of factors, including weathering of oil components and the presence of complex mixtures of substances. In other kinds of exposure settings and in some toxicologic studies, some of these substances and degradation products have been associated with a variety of chronic and/or long-term health effects. Therefore, people should be advised to minimize exposures to oil and dispersants in general, with particular attention to vulnerable populations and those with existing comorbidities.

Although some components of oil are known human carcinogens (such as benzene), associated cancer risks are difficult to assess due to a number of factors that affect exposure and influence health outcomes, including:

  • Weathering and degradation of oil components;

  • Level of adherence to exposure prevention efforts;

  • Individual susceptibility;

  • Other common exposures to carcinogens;

  • The particular circumstances surrounding the exposure; and

  • Routes of exposure.

The CDC is working closely with the EPA and other partners to attempt to better assess potential exposures related to the oil spill among workers and the general public in the affected areas of the Gulf states.

To date, environmental assessments for various crude oil constituents in air, sediment, and water have revealed levels above the limit of detection in only 5%-15% of all samples. Environmental samples of oil constituents measured above the limits of detection have been at levels far below those associated with any long-term health effects. In conducting this assessment, the CDC is using the most conservative estimates of exposure possible, for example, 70 years of exposure even though the vast majority of exposures will occur over days, weeks, or months. On the basis of our current assessment and understanding of exposures, the likelihood of long-term health effects, including cancer, remains low, but scientific gaps exist in our knowledge. The CDC is working closely with many partners and stakeholders, including affected communities, to further evaluate and better understand the longer-term health effects.

At the request of the US Department of Health & Human Services, the IOM held a public workshop in June to draw upon the best scientific expertise available to examine a broad range of health issues resulting from the oil spill, including:

  • Reviewing the current knowledge about the effects on human health of exposure to oil, weathered oil products, and dispersants, and identifying gaps in this knowledge;

  • Reviewing and assessing ways to monitor the spill's potential negative effects on health in the short and long term; and

  • Exploring methods and strategies for gathering data to further our understanding of the risks to human health.

The report from this workshop is due in August 2010 and will be posted on the IOM Website.


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